I have found a source for sheets or rolled aluminum in Wisconsin but I need to know what alloy I should order. I'm hoping to get a little help from the experts. I am wondering which alloy is resistant to denting yet is flexible enough to form around the curves of my camper. Oh and also doesn't break the bank. I am thinking .040" or .050" thicknessThanks,Scott

I'm not sure the alloy is really that important for trailer skins.Back when I designed machine parts we made alloy choices to consider strength, or machinability, or resistance to galling, or weldability, or the ability to get a clean edge on holes punched in panels, or the ability to be stamped into deep draws without cracking. Most aluminum alloys have two numbers The first four specify the metallurgy, and the last bit specifies the hardness from heat treating or other processes.

The alloy 2024, for example, is available as 2024 -0, 2024 -T3, 2024-T4, and 2024-T351Some are annealed, some are heat treated, some are age-hardened.None of that stuff matters very much in a cosmetic teardrop skin, unless you are bonding it and stressing it and need to know it's strength pretty accurately.

I believe 2024 T-3 is the most popular choice for airstream exterior builds and repairs.

5052 is like a "premium" upgrade to 3003. Stronger, more dent resistance, better corrosion resistance, etc. It's more expensive than 3003, but not hugely. Harder to find, though.

6061 is structural strength aluminum. Very pricey. Does not easily bend over tight curves.

What thickness you specify for your skin depends partially on how you attach it to your wall. Assuming you're not doing anything funky with your walls or roof, I would say that 0.040 thickness is all you need. Even 0.032 works extremely well. The only reason I would go thicker is if you're using the skin for structural strength or building a rock-crawler.

I can say 2024 T3 is heat treated and used in aviation for aircraft. 2024-O is annealed. It's in a soft condition, requiring heated to a set temperature and allowed to set before it reaches T-3 state. T-351 I thought was extruded, not sure. 2024 is expensive. 6061 and I think 5052 are weldable. 3000 series is what I recall is also known as refrigeration aluminum. I used it to cover my tear. It cheaper, $60 for 4 x 8 sheet. Hope this helps!!